Matarix resin for high-temperature stable photoimageable compositions

Abstract

The present invention relates to a novel matrix resin for high-temperature stable photoimageable compositions, in the form of a graft copolymer of monomeric or lower oligomeric hydroxyphenyl units grafted onto a polymer backbone containing reactive sites, to a process for its production and to its use as a matrix resin in photoimageable compositions either in a pure form or in admixture with other polymeric materials.

What is claimed is: 
     
       1. A process for preparing a composition useful as a matrix resin in a photoimageable composition..consisting essentially of a parent polymer containing aromatic rings with reactive sites to Which graft groups of the general formula are attached by a covalent bond: ##STR15## wherein R 1  to R 4  are hydrogen, C 1  to C 4  alkyl, hydroxy or methylene aryl groups of the general formula: ##STR16## where R 5  to R 8  are hydrogen, C 1  to C 4  alkyl or hydroxy wherein the number of aromatic rings in the graft group is 1 to 4, wherein the process comprises mixing the parent polymer and the graft groups in a nucleophilic addition reaction under conditions conducive to the formation of a covalent chemical bond between the graft groups and the parent polymer. 
     
     
       2. The process of claim 1 wherein the parent polymer is a homo- or co-polymer of a hydroxy-substituted styrene. 
     
     
       3. The process of claim 2 wherein the parent polymer is a homo- or co-polymer of hydroxystyrene, 3-hydroxystyrene or 2-hydroxystyrene. 
     
     
       4. The process of claim 1 wherein the graft groups are substantially all-ortho bonded novolak units of the general structure: ##STR17## where R 9  to R 15  are independently H, hydroxy, or C 1  to C 4  alkyl, and where n is 0 to 3. 
     
     
       5. The process of claim 4 wherein n is 0 or 1, and R 2 , R 5 , and R 7  are methyl, and R 1 , R 3 , R 4 , and R 6  are hydrogen. 
     
     
       6. The process of claim 1 wherein the graft groups are a monomeric methylene phenol or a mixture of methylene phenols. 
     
     
       7. The process of claim 6 wherein the monomeric graft groups are chosen from one or more of 4-hydroxybenzyl alcohol, 2-hydroxybenzyl alcohol, 3-hydroxybenzyl alcohol, 2-hydroxymethyl-p-cresol, 2-hydroxymethyl-m-cresol, 4-hydroxymethyl-m-cresol, 6-hydroxymethyl-2,4-xylenol, or 4-hydroxymethylresorcinol. 
     
     
       8. A method of using a composition as a matrix resin in a photoimageable material, wherein the photoimageable material is applied to a substrate and the composition consists essentially of a parent polymer containing aromatic rings with reactive sites to which graft groups of the general formula are attached: ##STR18## where R 1  to R 4  are hydrogen, C 1  to C 4  alkyl, hydroxy or methylene aryl groups of the general formula: ##STR19## where R 5  to R 8  are hydrogen, C 1  to C 4  alkyl or hydroxy wherein the number of aromatic rings in the graft group is 1 to 4.